SikaProof 312 HDPE SG W IN — Pre-Applied Fully Bonded Waterproofing Sheet Membrane

SikaProof®-312 HDPE SG W IN is a pre-applied, fully bonded waterproofing sheet membrane from Sika India — built around a virgin high-density polyethylene (HDPE) layer, a pressure-sensitive adhesive, and a weatherproof sand-sprinkled coating. Featuring a heat-weldable selvedge (W) for thermal jointing, it is laid down before concrete is poured to form a permanent mechanical and chemical bond directly with the fresh structure.

That permanent bond is what separates SikaProof-312 from surface-applied waterproofing chemicals and post-applied membranes. Because the sheet fuses with the wet concrete itself, water cannot track laterally between the membrane and the structure even if the sheet is punctured — leakage stays localised, making detection and repair dramatically simpler on basement waterproofing and below-grade projects.

The heat-weldable selvedge edges take joint integrity seriously. Built-in hot-air weldable selvedges allow overlapping joints to be physically fused together — not just overlapped — ensuring continuous seam security even under extreme groundwater pressure. For waterproofing contractors handling tunnels, podium slabs, or deep foundation work, that seam reliability removes one of the most common failure points in below-ground waterproofing solutions.

Practically, SikaProof-312 saves significant time and cost on site too. Its exceptional anti-puncture performance allows steel reinforcement bars to be tied directly on top of the sheet — eliminating the need for a separate protective concrete screed entirely. With elongation at yield of up to 550% to accommodate ground settlement and structural distortion, and tough long-term resistance against aggressive groundwater chemicals, sulfates, chlorides, alkalis, heat, and ozone — this is a construction chemical membrane built for the full structural lifecycle, not just the first few years.